PECAM1 and myocardial infarction: Endothelial cells labelled with the Cdh5Cre allele were mostly CD31 positive and only a small portion were co-labelled for vimentin, while none were αSMA expressing further suggesting that endogenous endothelial cell lineages do not generate myofibroblasts in the heart with MI injury (Fig. 5i and Supplementary Fig. 7).